Effects Of Different Biomaterials For Alveolar Ridge Preservation:an Experimental Study In Vivo

Objective:To investigate the performance of advanced platelet-rich plasma（A-PRF）,Bio-Oss?,Bio-Oss?Collagen and their mixtures on the early osteogenesis of alveolar ridge preservation.Methods:Twenty-seven Male New Zealand white rabbits were randomly divided into groups A,B and C,with 9 rabbits in each group.The extraction sockets of bilateral mandibular central incisor were set as the experimental sites.In group A,the sockets were filled with blood clot on the left（AL）and Bio-Oss?on the right（AR）.Group B was filled with bio-Oss?+A-PRF on the left（BL）and A-PRF on the right（BR）.Group C was filled with Bio-Oss?Collagen+A-PRF on the left（CL）and Bio-Oss?Collagen+A-PRF on the right（CR）.At 2,4 and 8 weeks after the operation,3 animals were randomly selected from group A,B and C to extract the anterior mandible as specimens after euthanasia.After the reconstructed specimens of Micro-CT scan to the new data set,the image centroid was formulated with the mandibular suture and longest horizontal axis.The volume of interest（VOI）,labeled as 1mm~3 tissue block,was adjacent to the alveolar wall to the shortest distance from the centroid.Bone mineral density（BMD）,bone trabecular thickness（Tb.Th）and structural model index（SMI）were used as analysis indexes.Hematoxylin-eosin staining（HE）and tartrate-resistant acid phosphatase staining（TRAP）were adopted to observe the histological characteristcs of each group.Results:All the experimental animals had no accidental healing and the mandible was extracted successfully.1)Micro-CT results:BMD showed that,at 2 weeks,AL and BR groups were higher than the other four groups,but there was no statistical difference（P>0.05）.At 4 weeks,the BR group was significantly higher than the AR group（P<0.05）while the comparison between the other groups did not have statistical significance.At 8 weeks,AL and AR groups were significantly higher than AR,BL and CL groups（P<0.05）.Tb.Th indicated that AL and BR groups were higher than that of other four groups.However,only the AL group at 4 weeks and AR group at 8 weeks had statistical significance（P<0.05）.SMI revealed that rod-shaped trabecular bone was dominant in AL and BR groups,while lamellar bone was mainly in the other four groups,and there was no statistical difference among the four groups（P>0.05）;2)Compared with AL group,BR group was more active in new bone trabeculae,new blood vessels and bone marrow.The histological performance of AR,BL,CL and CR groups were similar.Except osteoclasts,no new bone was observed on the surface of grafted particles at 2 weeks.At 4 weeks,osteogenesis was active on the surface of particles,but the particles were not completely encapsulated.At 8weeks,new bone wrapped the particles to integarate a whole and osteoclasts were rare at this time.Conclusion:Employing A-PRF alone could promote the healing of extracted socket,although the osteogenic effect might be affected by the dose of A-PRF.Meanwhile,Bio-Oss?and Bio-Oss?Collagen had similar behaviors in ARP,which delayed the socket healing and lacked osteogenesis.When A-PRF was mixed with Bio-Oss?or Bio-Oss?Collagen,the effect of promoting healing was not obvious.